IV. DEINOSUCHUS HATCHERI, A NEW GENUS AND SPECIES OF CROCODILE FROM THE JUDITH RIVER BEDS OF MONTANA.
By W.J. Holland
Upon the occasion of the geological reconnaissance undertaken by Mr. T. W. Stanton and Mr. J. B. Hatcher under the auspices of the United States Geological Survey in the summer of the year 1903, Mr. Hatcher found on Willow Creek, three miles west of Nolan and Archer's ranch, in Fergus County, Montana, some fragmentary remains lying upon the surface of the soil. He picked up a couple of scutes, which he brought back with him to the Carnegie Museum, and at the same time referred them provisionally to Stereocephalus tutus Lambe. Mr. W. H. Utterback was sent to the locality by Mr. Hatcher in the fall of 1903 with instructions to thoroughly explore the spot, and recover whatever could be found.
Mr. Utterback only succeeded in finding two vertebrae, one cervical rib, one fairly complete dorsal rib, fragments of other dorsal ribs, an os pubis, a large number of scutes, some of them quite perfect, and several hundred fragments of bones, some of them no doubt belonging to the skull, others to the vertebrae and ribs, but all of them so badly broken, and a few even water-worn, that it is impossible to refer them with any degree of certainty to their true position. The vertebrae and the ribs upon examination conclusively demonstrated, as the writer pointed out to Mr. Hatcher, that the animal was a huge crocodile. Mr. Hatcher immediately lost interest in the material, and though on several occasions urged to figure and describe the bones, turned from them to other things, which at the time possessed greater interest, and then came his untimely and melancholy end.
In 1905 Professor S. W. Williston urged the writer to describe the specimen, but, though the work was begun, it is only recently that the writer has found time to complete the brief sketch of these interesting remains, which is here given.
The type (No. 963 Carnegie Museum Catalog of Vertebrate Fossils) consists of two vertebrae; a cervical rib; the first dorsal rib of the left side; fragments of several other dorsal ribs; an os pubis; twenty-five scutes in fairly good condition, and numerous fragments of others; and in addition several hundreds of comminuted fragments of vertebrae, ribs, and bones of the skull, which furnish no contacts, and defy efforts to successfully collocate them. Some of these fragments are more or less water-worn, and consist simply of bits of bone which were for the most part found by Mr. Utterback upon the surface, where the skeleton had been weathered out, and trodden under foot. Some of them suggest that they have been exposed to the action of fire, and this might well have been the case when prairie-fires swept over the spot.
Generic characters of Deinosuchus so far as known. Great size, exceeding that of any other representative of the Crocodilia thus far described from North America. Scutes massive and possessing great vertical height in comparison with their breadth, many of the smaller scutes being almost hemispherical, and some of the smallest subglobose. Pubis straighter and less deeply excavated posteriorly than in recent crocodilia. Extremities of dorsal spines of vertebrae broad transversely and thickened for attachments, much more so than in existing genera. The postzygapophyses of the vertebrae more nearly on the same plane as the transverse processes and not looking outwardly as much as in other crocodiles.
SEVENTH (?) DORSAL VERTEBRA. The specimen, which almost beyond a doubt is the seventh in the dorsal series, is the better preserved of the two vertebrae which were recovered. It is procoelous. At the extremities of the transverse processes it shows the articulating surfaces for the ribs. It is a very massive bone and the dorsal spine is broad above, being greatly thickened transversely for attachment to adjacent structures. The postzygapophyses do not look as strongly outwardly as in the recent crocodilia, the under surfaces lying at their outer extremities nearly in the same plane as the upper surface of the transverse processes. Three views of the vertebra are given in Figures 1-3.
LAST (?) LUMBAR VERTEBRA.